/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.flink.util;

import org.junit.jupiter.api.Test;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;

/** Tests for {@link WrappingProxyUtil}. */
class WrappingProxyUtilTest {

    @Test
    void testThrowsExceptionIfTooManyProxies() {
        assertThatThrownBy(
                        () ->
                                WrappingProxyUtil.stripProxy(
                                        new SelfWrappingProxy(
                                                WrappingProxyUtil.SAFETY_NET_MAX_ITERATIONS)))
                .isInstanceOf(IllegalArgumentException.class)
                .hasMessageContaining("Are there loops in the object graph?");
    }

    @Test
    void testStripsAllProxies() {
        final SelfWrappingProxy wrappingProxy =
                new SelfWrappingProxy(WrappingProxyUtil.SAFETY_NET_MAX_ITERATIONS - 1);
        assertThat(WrappingProxyUtil.stripProxy(wrappingProxy))
                .isNotInstanceOf(SelfWrappingProxy.class);
    }

    private static class Wrapped {}

    /** Wraps around {@link Wrapped} a specified number of times. */
    private static class SelfWrappingProxy extends Wrapped implements WrappingProxy<Wrapped> {

        private int levels;

        private SelfWrappingProxy(final int levels) {
            this.levels = levels;
        }

        @Override
        public Wrapped getWrappedDelegate() {
            if (levels-- == 0) {
                return new Wrapped();
            } else {
                return this;
            }
        }
    }
}
